[Oracle/Client] Report card database download progress

Card database updates ran invisibly: MTGJSON parsing spun an indeterminate
bar on the UI thread and the set import blocked the window, while the
onboarding wizard spawned `oracle -b` with no progress to show at all.

- Add byte-level scan progress to `RawJson::scanSetRanges` via an optional
  callback, throttled to ~100 reports per scan.
- Emit `OracleImporter::dataReadProgress` during the scan and import sets on a
  worker thread, driving the wizard's progress bar per set.
- With `-b`, write machine-readable `PROGRESS <stage> <done> <total>` lines to
  stdout for the download/scan/import stages; stderr keeps the log output.
- Parse the oracle stdout in `MainWindow` and forward it to the onboarding
  wizard, giving the card database step a determinate bar with stage-specific
  status text.
- Guard the async workers against the wizard being closed mid-run.
- Add Google Test coverage for scan progress reporting.

cockatrice/src/interface/window_main.cpp

@@ -682,6 +682,7 @@ void MainWindow::runFirstRunWizard()
     connect(wizard, &FirstRunWizard::cardDatabaseUpdateRequested, this, &MainWindow::actCheckCardUpdatesBackground);
     connect(wizard, &FirstRunWizard::manualCardDatabaseSetupRequested, this, &MainWindow::actCheckCardUpdates);
     connect(this, &MainWindow::cardDatabaseUpdateFinished, wizard, &FirstRunWizard::onCardDatabaseUpdateFinished);
+    connect(this, &MainWindow::cardDatabaseUpdateProgress, wizard, &FirstRunWizard::onCardDatabaseUpdateProgress);
     connect(wizard, &FirstRunWizard::registerRequested, connectionController, &ConnectionController::registerToServer);
     connect(wizard, &FirstRunWizard::connectRequested, connectionController, &ConnectionController::connectToServer);
 
@@ -1057,11 +1058,45 @@ void MainWindow::createCardUpdateProcess(bool background)
     if (!background) {
         cardUpdateProcess->start(updaterCmd, QStringList());
     } else {
+        cardUpdateOutputBuffer.clear();
+        connect(cardUpdateProcess, &QProcess::readyReadStandardOutput, this, &MainWindow::cardUpdateProgressOutput);
         cardUpdateProcess->start(updaterCmd, QStringList("-b"));
         statusBar()->showMessage(tr("Card database update running."));
     }
 }
 
+void MainWindow::cardUpdateProgressOutput()
+{
+    if (!cardUpdateProcess) {
+        return;
+    }
+    cardUpdateOutputBuffer.append(cardUpdateProcess->readAllStandardOutput());
+    while (true) {
+        const int newline = cardUpdateOutputBuffer.indexOf('\n');
+        if (newline < 0) {
+            break;
+        }
+        const QByteArray line = cardUpdateOutputBuffer.left(newline).trimmed();
+        cardUpdateOutputBuffer.remove(0, newline + 1);
+        // Protocol emitted by `oracle -b`: "PROGRESS <stage> <done> <total>"
+        if (!line.startsWith("PROGRESS ")) {
+            continue;
+        }
+        const QList<QByteArray> parts = line.split(' ');
+        if (parts.size() != 4) {
+            continue;
+        }
+        bool doneOk = false;
+        bool totalOk = false;
+        const qint64 done = parts.at(2).toLongLong(&doneOk);
+        const qint64 total = parts.at(3).toLongLong(&totalOk);
+        if (!doneOk || !totalOk || done < 0 || total < 0) {
+            continue;
+        }
+        emit cardDatabaseUpdateProgress(QString::fromLatin1(parts.at(1)), done, total);
+    }
+}
+
 void MainWindow::exitCardDatabaseUpdate()
 {
     if (!cardUpdateProcess) {
@@ -1109,6 +1144,8 @@ void MainWindow::cardUpdateError(QProcess::ProcessError err)
 
 void MainWindow::cardUpdateFinished(int exitCode, QProcess::ExitStatus exitStatus)
 {
+    cardUpdateProgressOutput(); // drain any progress lines not yet parsed
+
     const bool success = (exitStatus == QProcess::NormalExit) && (exitCode == 0);
     if (exitStatus == QProcess::NormalExit) {
         SettingsCache::instance().updates().setLastCardUpdateCheck(QDateTime::currentDateTime().date());